<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    input:disabled {
      outline: 2px solid red;
    }

    input:enabled {
      outline: 2px solid blue;
    }
  </style>
</head>

<body>
  <h2>11.html</h2>
  <form>
    <p>
      <input disabled type="text" id="username" checked>
    </p>
    <p>
      <input type="text" id="password" checked>
    </p>
    <p>
      <input disabled type="text" id="age" checked>
    </p>


  </form>

</body>

</html>